The present invention relates generally to an improved device for clampingly securing a wire or cable to a work surface.
Clamping devices of this general type have been known and utilized with varying degrees of effectiveness. The various improvements constituting this invention were the results of attempts to overcome problems incurred by the device invented by E. Grant Swick, U.S. Pat. No. 4,127,250. That invention was assigned to and is commonly owned with this invention by Illinois Tool Works Inc. Other prior art includes the routing of cables by staples having a compressible bridge material.
Except for the device disclosed in the patent to Swick (U.S. Pat. No. 4,127,250), there are no known wire routing devices adapted to be used with many different supporting surface, including concrete. The particular problems in fastening a routing device to concrete are different from those which are encountered in fastening to surfaces which have less structural integrity. The original Swick device answered the overall problem of a universal device by providing a plastic block, of a very durable material such as Lexan polycarbonate, with a recess crossing one surface adapted to receive and clip to a wire and a pair of hardened steel pins suited to be struck by a hammer and driven into the support surface, e.g., concrete.
The set of problems that are attributable to the prior art devices include:
(1) the plastic block often being broken due to too much energy being imparted thereto by the tool used to drive the pins; PA0 (2) the block only being capable of routing a single size of wire; PA0 (3) the block breaking when one pin had been driven into concrete and as the second pin was driven it encountered a substantially impenetrable piece of aggregate and attempted to avoid it; PA0 (4) the block not being seated flush with the support surface because of spalling of the concrete as the pin began its penetration with the problem being compounded by the downward extrusion of the plastic block by the pin; PA0 (5) the block damaging the support surface when the surface is of a lesser structural integrity due to the large impacting force necessary to drive the pins through the block. PA0 (1) an impact absorbing ring, which crushes on impact, for absorbing the excess energy of the tool used to drive the pin; PA0 (2) a plurality of recesses for routing of various sizes and configurations of wire and cable; PA0 (3) a provision for permitting the point of the pin to avoid a substantially impenetrable object, e.g., a piece of aggregate in concrete; PA0 (4) a cylindroconical bore that has a different included angle in the frustoconical portion relative to the included angle of the frustoconical portion of the pin to permit the plastic directly in line with the end of the cylindroconical bore to extrude upwardly around the pin as it is driven to thereby provide a compaction of the area of the support surface where the pin penetrates; PA0 (5) predriving of the pins in the block with the pins being retained in the predriven condition to thereby permit attachment of the same routing device to support surfaces having lesser structural integrity, e.g., stucco or plaster, by a blow of less force then that required to drive the pins through the block and into the support surface.
The present invention has answered the above noted problems, as will be discussed hereinafter.